Nord-Trøndelag was a county constituting the northern part of the present-day Trøndelag county in Norway. It bordered the old Sør-Trøndelag county as well as the county of Nordland. To the west is the Norwegian Sea, and to the east is Jämtland in Sweden. The county was established in 1804 when the old Trondhjems amt was divided into two: Nordre Trondhjems amt and Søndre Trondhjems amt. In 2016, the two county councils voted to merge (back) into a single county on 1 January 2018.

Trøndelag (Urban East Norwegian: [ˈtrœ̂ndəˌlɑːɡ]; or Trööndelage  is a county and coextensive with the Trøndelag region in the central part of Norway. It was created in 1687, then named Trondhjem County ; in 1804 the county was split into Nord-Trøndelag and Sør-Trøndelag by the King of Denmark-Norway, and the counties were reunited in 2018 after a vote of the two counties in 2016.